From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx0b-00082601.pphosted.com (mx0b-00082601.pphosted.com [67.231.153.30]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C89F94F5E14 for ; Tue, 22 Sep 2026 07:30:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=67.231.153.30 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790062210; cv=none; b=tv+8fepFZ5NfUvqCbyrtvoQHsg3xJmZ5Lsu7atHgUV0e0fIv4gev6nNrWZHQNwXo3Z0quNQtFeFxNtspFyeMiqzkjHhp/y+gLnwZ9yvHrwNn19drX7bU08LoQSfpeWaF97as4nDi7czzKIb0igQwMFJj+mLmsFvVrhBPaDJKjcg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790062210; c=relaxed/simple; bh=e0wwLm6GVdk/4eLZWaOk+hFka1eOw+pZRQeFcIo+OLM=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=ctIaN+ZsEFrEDpCeYnucaP0Cqd/jBq+nCiMauVD5MF/ZTv+dm52l4t8WIAaweDnd3IvmjLOp5DDbjiIcaa1fganr3Xn9Dhte9FXzwnYHzLJUL/pnOXMI1vUIuFZzQAVDydTbvaoxCKGI/5NAAWoYnbC9YqDzDIZinQBIFFO3Cxw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=meta.com; spf=pass smtp.mailfrom=meta.com; dkim=pass (2048-bit key) header.d=meta.com header.i=@meta.com header.b=CVtscwdR; arc=none smtp.client-ip=67.231.153.30 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=meta.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=meta.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=meta.com header.i=@meta.com header.b="CVtscwdR" Received: from pps.filterd (m0109332.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.18.1.11/8.18.1.11) with ESMTP id 68M38Tm02316803 for ; Tue, 22 Sep 2026 00:30:05 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=meta.com; h=cc :content-transfer-encoding:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to; s= pps82601-s2048-2026-q3; bh=bP6Zss+aaOzHcwIebwVFpv7fhWLwx4mxZ4iL6 pHj1yI=; b=CVtscwdRVu42P7exdoDACeAH+rmFb0al9rSK6TZQ/LQ+cC5xZkshn ZshkvQmIvUJMocGI2D2yWKFvV0X8sUuoJVIzh7mjflnxlT8P1H+88kJZ4Oet9kw0 Vi4Nz/n1mgqyWvPrJ+qiRTiQYHXYnZ5wjapj7jn9eId1MMgBYT2gicVbAizeAwHg KAXUKhkuIbj0soMN4ihhCfmWNFQQ5dX46Cjorz7yitVzRbXlA0KG1+SELucLoiRX jCZ+1IekPpH1Cy/yYvZu9OYhB4Rbi7vniAmPegu38mNDVa1GDIyzwzeoCp7bhlnK fkKfSQVlHik2Dk7yNfP5b9MyHhq1kd3RQ== Received: from mail-wr1-f69.google.com (mail-wr1-f69.google.com [209.85.221.69]) by mx0a-00082601.pphosted.com (PPS) with ESMTPS id 4gsr4cb9ay-1 (version=TLSv1.3 cipher=TLS_AES_128_GCM_SHA256 bits=128 verify=NOT) for ; Tue, 22 Sep 2026 00:30:05 -0700 (PDT) Received: by mail-wr1-f69.google.com with SMTP id ffacd0b85a97d-4843cff4a2dso67938f8f.2 for ; Tue, 22 Sep 2026 00:30:04 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1790062204; x=1790667004; h=content-transfer-encoding:content-type:in-reply-to:from :content-language:references:cc:to:subject:user-agent:mime-version :date:message-id:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=CUwnAJCHxe3FXOwxQjHfEXhUqFJyKsr1HhIR5z/gcsk=; b=hRQD5pzzQQMaGnL1HVeQWZoSWO30P9zgWCQPhHJY0e5pVEioZx6SDYrbqbDbtIQ9hJ 0KgKfRfEuOj3lI1KQRZ3a5PKuWJcDuit63TEsLagBu9rTEI+t0/wf/ccBqjC/EOCfjGc PbqfCaEyVpgLsP5NdEni0E6rc8WVxf58xjboeKnWcB7iiFc4lnFtFoVwtBibb/g6vAD9 zF1dwoWK3RtgmH1VcDruMPorS8uO1XHv0I8OEr0UaEcvgWlIHURop+fUS3kX6WFQS3Xr Bd/xXafE/DtNVi5X9lvuhUyYKVs5f+t+21e+Prw+TUlh0iwJ5CDeaL1MT6l+a+i4dW6c YrOA== X-Forwarded-Encrypted: i=1; AKwUvByNoi8rMOnbEyruuji9hnOrufMKEpPeZNuiiS9F+42TGDIQDxXSl30UYkfF85m7oFvqbXOt0Sc=@vger.kernel.org X-Gm-Message-State: AFuF++lweWoYwrDX6UVtZ36FLO0qJuIeKusfdKSEBYjNrnilFevMS1jr EApK5k/ctb40txSLAyqAOr4c/r2J17pG/7QBH8SliBbnd9N5ILK3OGEN3gJtBRxaEwb7mTdv7O7 28qZxpYpqPuXLEE8c9bp/KksJww3iF5nZbMCiU5fOa2SFZnxMlAy4kg2m X-Gm-Gg: AYBFou1PrJb1B4QHpTAkR9Lc7a3J1QuwEN4UDgBvqgiDtdf7pYvL6enax7dnV52ulQb mpJxFbYr/X4Gl3l8lg2rSrN3a+Dqir727grWeAokoFd1UqShaHSzUYPNfQAG5uGGfFf8bVhx37K 30/jkR4DckSnY/OwQapeL7EeE1P5mWF9K0Q5xpAM4+RxGutsrjXXT+UjwbbbICL7NghwWgN4xqA 6b9V3ER4HiAuPK11zEl6vr9RYskhK1HLTM5cvv5VlK1ma0UtwVlHo+7+ol0w+fBNKbwxYVmFxY5 kUrgAIn9A0vc7DH+mO8fiJgmwYhseLrLmpZ7Q+4wFc9W6GsO5L3YBdPfW6eywFEtrxCqyT7RL1v fwt8IF7ycIYnUv6ib6vMgL1/smT+udJhK9fOXuq0= X-Received: by 2002:a05:6000:4010:b0:487:981:4e07 with SMTP id ffacd0b85a97d-4871fa86624mr17627945f8f.4.1790062203850; Tue, 22 Sep 2026 00:30:03 -0700 (PDT) X-Received: by 2002:a05:6000:4010:b0:487:981:4e07 with SMTP id ffacd0b85a97d-4871fa86624mr17627909f8f.4.1790062203407; Tue, 22 Sep 2026 00:30:03 -0700 (PDT) Received: from ?IPV6:2a01:e0a:e17:9700:3f7b:7276:a343:d339? ([2a01:e0a:e17:9700:3f7b:7276:a343:d339]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-48862731429sm2278905f8f.5.2026.09.22.00.30.02 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 22 Sep 2026 00:30:02 -0700 (PDT) Message-ID: Date: Tue, 22 Sep 2026 09:29:58 +0200 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH bpf-next 6/7] bpf: tcp: Add kfunc to adjust sk->sk_rcvlowat. To: Kuniyuki Iwashima , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Eduard Zingerman , Kumar Kartikeya Dwivedi Cc: Yonghong Song , John Fastabend , Stanislav Fomichev , Eric Dumazet , Neal Cardwell , Willem de Bruijn , Tenzin Ukyab , Kuniyuki Iwashima , bpf@vger.kernel.org, netdev@vger.kernel.org References: <20260920195633.3033620-1-kuniyu@google.com> <20260920195633.3033620-7-kuniyu@google.com> Content-Language: en-US From: =?UTF-8?B?Q2zDqW1lbnQgTMOpZ2Vy?= In-Reply-To: <20260920195633.3033620-7-kuniyu@google.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable X-Proofpoint-ORIG-GUID: RLMqBIJufnfm3Yv4NFEa7nh9MEjxOIYH X-Authority-Analysis: v=2.4 cv=SKnXx+vH c=1 sm=1 tr=0 ts=6ab22e7d cx=c_pps a=CsXZvLRfiTx/ye2xXAwb9g==:117 a=xqWC_Br6kY4A:10 a=IkcTkHD0fZMA:10 a=VdqzKS8jKosA:10 a=M51BFTxLslgA:10 a=VkNPw1HP01LnGYTKEx00:22 a=7x6HtfJdh03M6CCDgxCd:22 a=xtH7KyWI9dI7BmFOsl-x:22 a=1XWaLZrsAAAA:8 a=VabnemYjAAAA:8 a=sLGjIoZK2OyoYNR-nVkA:9 a=3ZKOabzyN94A:10 a=QEXdDO2ut3YA:10 a=F7q00xkr9EfWfQvbdVXI:22 a=gKebqoRLp9LExxC7YDUY:22 X-Proofpoint-Spam-Info: AW1haW4tMjYwOTIyMDEwNiBTYWx0ZWRfX4DzRsHXjKAoK vN6YzHoWmngZvswQXrB1dh5j0Af052PK4vITlt6tw8/A4ZZmz8kKjjPWUHFBt2W7AhIXyaaiiak kU/it8XPzJ2C2+uQZKyZ205Jktj7Je8= X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwOTIyMDEwNiBTYWx0ZWRfX/7r9AoEnPgpc sUiZr49wa8qSliwClr6NPQ6IfQMH4hb0Bbe4gPYb7fX2APeqZUkFMJuD1YDYg5k8luoGREeW20w fEERJcNrgNfaihaMPOJr56yVwQZX/mae4HrY0gKqeQG5MBBzzsj2w6GlcsnMSA2blwXqLKgS8G5 wPKP24BFMu1yCS1jKI6ls3hjSfvGxBD7sQYU+eHURMUf1gWZio1bdD7SNaLEJpoTAY5EYdIfKmp e4xf8mL3HTFGS+TwbmBpAIRgTQglwqVRcMC5Ad6t/ziumfsfg/HtqxKR+pZRsG9x8yCBsXxqWVG g96Spji5HEmg3CrCtMB40UQevHbjiSWsrXpzes1+RfecK8ANo4gKgBxEEvGREmrJIouMfdbG/L3 twu+wYyGuUCq3ANR4BcQS7nL8CdFaJNXmFBgm9xHXT7TVQ817BmMSuQfolRgX+yxZ7p/xPUSyYQ JQu3kbjo89obyvhEX+A== X-Proofpoint-GUID: RLMqBIJufnfm3Yv4NFEa7nh9MEjxOIYH X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-09-21_07,2026-09-21_02,2025-10-01_01 On 9/20/26 21:56, Kuniyuki Iwashima wrote: > >=20 > bpf_tcp_ops.{enqueue,dequeue}_rcvq() were added to parse skb and > adjust sk->sk_rcvlowat dynamically to suppress unnecessary wakeups. >=20 > Let's add a new kfunc to set sk->sk_rcvlowat. >=20 > Negative values are clamped to INT_MAX, consistent with SO_RCVLOWAT. >=20 > For enqueue_rcvq(), wakeup is set to false because: >=20 > * tcp_data_ready() is always called after the hooks in > tcp_queue_rcv() and tcp_ofo_queue(). >=20 > * when tcp_fastopen_add_skb() is called for TFO SYN, the socket is > not yet accept()ed, and when called for TFO SYN+ACK, the socket > is woken up by sk->sk_state_change() anyway. >=20 > For dequeue_rcvq(), wakeup is set to true because tcp_data_ready() > is not called in that path. >=20 > An alternative would be to support bpf_setsockopt() for these > hooks. >=20 > However, that approach involves excessive conditionals and an > unnecessary memcpy(), costs we do not want to pay for every skb > in the TCP fast path. >=20 > Signed-off-by: Kuniyuki Iwashima > --- > net/ipv4/bpf_tcp_ops.c | 56 +++++++++++++++++++++++++++++++++++++++++- > 1 file changed, 55 insertions(+), 1 deletion(-) >=20 > diff --git a/net/ipv4/bpf_tcp_ops.c b/net/ipv4/bpf_tcp_ops.c > index b0e14b54917e..3768b1440eb7 100644 > --- a/net/ipv4/bpf_tcp_ops.c > +++ b/net/ipv4/bpf_tcp_ops.c > @@ -359,8 +359,62 @@ static struct bpf_struct_ops bpf_tcp_ops =3D { > .owner =3D THIS_MODULE, > }; > =20 > +__bpf_kfunc_start_defs(); > + > +__bpf_kfunc int bpf_tcp_ops_set_rcvlowat(struct sock *sk, int rcvlowat, > + const struct bpf_prog_aux *aux) > +{ > + u32 moff =3D aux->attach_st_ops_member_off; > + bool wakeup =3D false; > + > + if (moff =3D=3D offsetof(struct bpf_tcp_ops, dequeue_rcvq)) > + wakeup =3D true; > + > + if (rcvlowat < 0) > + rcvlowat =3D INT_MAX; > + > + return __tcp_set_rcvlowat(sk, rcvlowat, wakeup); > +} > + > +__bpf_kfunc_end_defs(); > + > +BTF_KFUNCS_START(bpf_tcp_ops_rcvlowat_kfunc_set) > +BTF_ID_FLAGS(func, bpf_tcp_ops_set_rcvlowat, KF_IMPLICIT_ARGS) > +BTF_KFUNCS_END(bpf_tcp_ops_rcvlowat_kfunc_set) > + > +static int bpf_tcp_ops_rcvlowat_kfunc_filter(const struct bpf_prog *prog, > + u32 kfunc_id) > +{ > + u32 moff; > + > + if (!btf_id_set8_contains(&bpf_tcp_ops_rcvlowat_kfunc_set, kfunc_id)) > + return 0; > + > + if (prog->aux->st_ops !=3D &bpf_tcp_ops) > + return -EACCES; > + > + moff =3D prog->aux->attach_st_ops_member_off; > + if (moff !=3D offsetof(struct bpf_tcp_ops, enqueue_rcvq) && > + moff !=3D offsetof(struct bpf_tcp_ops, dequeue_rcvq)) > + return -EACCES; > + > + return 0; > +} > + > +static const struct btf_kfunc_id_set bpf_tcp_ops_rcvlowat_kfunc_id_set = =3D { > + .owner =3D THIS_MODULE, > + .set =3D &bpf_tcp_ops_rcvlowat_kfunc_set, > + .filter =3D bpf_tcp_ops_rcvlowat_kfunc_filter, > +}; > + > static int __init __bpf_tcp_ops_init(void) > { > - return register_bpf_struct_ops(&bpf_tcp_ops, bpf_tcp_ops); > + int ret; > + > + ret =3D register_btf_kfunc_id_set(BPF_PROG_TYPE_STRUCT_OPS, > + &bpf_tcp_ops_rcvlowat_kfunc_id_set); > + ret =3D ret ?: register_bpf_struct_ops(&bpf_tcp_ops, bpf_tcp_ops); > + > + return ret; > } > late_initcall(__bpf_tcp_ops_init); Hi Kuniyuki, Tested-by: Cl=C3=A9ment L=C3=A9ger Thanks, Cl=C3=A9ment